Apparatus and methods for cleaning strip materials

ABSTRACT

APPARATUS AND METHODS FOR ULTRASONICALLY CLEANING FRAGILE STRIP MATERIALS, SUCH AS MOTION PICTURE FILM AND THE LIKE. THE STRIP MATERIAL IS PASSED IN A DOUBLE RUN THROUGH A SOLVENT BATH LOCATED WITHIN THE BORE OF A GENERALLY CYLINDRICAL ELECTROMECHANICAL TRANSDUCER. A MATERIAL TRANSPORT MECHANISM, IN PART SELECTIVELY RECIPROCABLE BETWEEN A THREADING POSITION ADJACENT ONE END OF THE TRANSDUCER BORE AND A RUNNING POSITION ADJACENT THE OTHER   END OF THE BORE, ALLOWS READY INTRODUCTION OF THE MATERIAL INTO THE BORE FOR CLEANING AND ALSO FACILITIES MATERIAL THREADING AND REMOVAL. THE SOLVENT BATH IS MAINTAINED WITHIN THE BORE BY IMMERSING THE TRANSDUCER IN AN EXTERNAL SOLVENT BATH OR BY ENCLOSNG ONE END OF THE TRANSDUCER BORE TO CONTAIN THE SOLVENT WITHIN THE TRANSDUCER ITSELF.

A. J. MILLER 3,582,400

APPARATUS AND METHODS FOR CLEANING STRIP MATERIALS June 1, 1971 FiledNov. 21, 1969 4 Sheets-Sheet 1 //"--FROM FEED REEL Ni/TO DRYER INVENTOR.ARTHUR J. MILLER BY M) his June 1,-1971 A. J. MILLER 3,582,400

APPARATUS AND METHODS FOR CLEANING STRIP MATERIALS Filed Nov. 21, 1969 4Sheets-Sheet 2 k-FROM FEED REEL v m E N INVENTOR. o ARTHUR J. MILLER BYhis A TTOR/VEYS Juhe 1, 1971 MlLLER 3,582,400

I APPARATUS AND METHODS FOR CLEANING STRIP MATERIALS Filed Nov; 21, 19694 Sheets-Sheet 5 INVENTOR. ARTHUR J. MILLER BY Ag v/J his ATTORNEYS June151971 J MULLER 3,582,400

I I APPARATUS .AND METHODS FOR CLEANING STRIP MATERIALS Filed uov. z1,1969 4 Sheets-Sheet 4 INVENTOR ARTHUR J. MlLLER swam Ms Arro NEKS UnitedStates Patent Oflice Patented June 1, 1971 3,582,400 APPARATUS ANDMETHODS FOR CLEANING STRIP MATERIALS Arthur J. Miller, Horizon TowersN., Fort Lee, NJ. 07024 Filed Nov. 21, 1969, Ser. No. 878,771

Int. Cl. B0811 7/00 U.S. Cl. 1341 17 Claims ABSTRACT OF THE DISCLOSUREApparatus and methods for ultrasonically cleaning fragile stripmaterials, such as motion picture film and the like. The strip materialis passed in a double run through a solvent bath located within the boreof a generally cylindrical electromechanical transducer. A materialtransport mechanism, in part selectively reciprocable between athreading position adjacent one end of the transducer bore and a runningposition adjacent the other end of the bore, allows ready introductionof the material into the bore for cleaning and also facilitates materialthreading and removal. The solvent bath is maintained within the bore byimmersing the transducer in an external solvent bath or by enclosing oneend of the transducer bore to contain the solvent within the transduceritself.

BACKGROUND OF THE INVENTION The present invention relates broadly toapparatus and methods for cleaning strip materials, and moreparticularly to improved ultrasonic cleaning apparatus and methods foruse with fragile strip materials such as motion picture film, magneticand video tape, and the like.

Because strip materials of the type mentioned have a great tendency toattract and retain foreign matter, and especially particulates such asdust, lint, etc., it is common practice in the use and the processing ofthese materials to clean them periodically in order to avoid thedeleterious effects which result from the presence of foreign matter onthe record-bearing surfaces of the materials. Such effects ofteninclude, for example, actual damage to the materials themselves, or adegradation in the fidelity of the reproduced record, or both.

Typically, cleaning of the strip materials, for instance, motion picturefilm, is accomplished by passing the film through a solvent bath,usually agitated ultrasonically, then through a rinsing station wherecontaminants picked up in the solvent bath are rinsed from the filmsurfaces, and finally through a dryer where the solvent or othermoisture adhering to the film is removed.

With such cleaning apparatus, it is highly desirable that the cleaningbe carried out at the maximum film feed rate possible commensurate withthorough cleaning of the film surfaces and the preservation of the filmin an undamaged condition. Foreconomy of space and operation, it is alsodesirable that the high film feed rates be achieved withoutcorresponding increases in the size of the cleaning apparatus, thequantity of solvent used or in the number or power consumption of thetransducers needed to agitate the bath.

Still another important consideration is that the film must be easilyrecoverable intact from the solvent bath at the end of, or at anyinterruption of, a cleaning run. Again, all components of the filmtransport mechanism used to carry the film through the apparatus,including the components which pass the film through the solvent bath,must be readily accessible to the operator both to facilitate threadingof the film on the transport mechanism and to permit removal of the filmfrom the mechanism without delay.

These and other requirements of the prior art are fulfilled by the novelcleaning apparatus and methods of the present invention.

SUMMARY OF THE INVENTION In accordance with the invention, fragile stripmaterials such as motion picture film, magnetic and video tapes, and thelike are cleaned upon being passed at high speed in a double run throughthe axial bore of a generally cylindrical electromechanical transducer.A solvent bath suitable for cleaning the material is provided within thebore and is agitated ultrasonically upon energization of the transducer,thus subjecting the material to a vigorous cleaning action as it travelsthrough the bore.

A transport mechanism for carrying the strip material includes a firstroll located adjacent one end of the transducer for guiding the materialaxially into the transducer bore and a second roll, movable between athreading position adjacent the first roll and a running position at theother end of the transducer, for receiving the strip moving from thefirst roll and returning it axially through the bore in the oppositedirection. The movable second roll is slidably mounted on a guide trackwhich extends axially through the transducer bore and is selectivelyreciprocated therealong between the threading and running positions byan appropriate drive system.

The transducer may be immersed in a solvent bath with one or both endsof the bore open to the bath, or the solvent bath may be contained inthe bore, in which case one end of the bore is capped with a fluidtightenclosure. The first roll and the threading position of the second rollare spaced axially outward of one end of the bore, while the runningposition of the second roll preferably is spaced axially outward of theopposite end of the bore. Where the solvent bath is contained within thebore, the running position of the second roll is located within theenclosure closing off the one end of the bore, but preferably is stillaxially outward of the end of the bore.

In a preferred embodiment of the invention, the bore of the transduceris located in a generally vertical plane, with the location of the firstroll and the threading position of the second roll being selected to beabove the level of the solvent bath. Accordingly, both the first andsecond rolls are readily accessible for threading of the strip materialat the beginning of the cleaning process. By the same arrangement, thestrip material is easily withdrawn from the solvent bath at any time.

The present invention, therefore, allows the high speed cleaning ofstrip materials at low operating cost, and additionally yields amarkedly compact unit that affords significant savings in space andsolvent usage over prior art cleaning devices.

BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of theinvention, reference may be made to the following description of anexemplary embodiment, taken in conjunction with the figures of theaccompanying drawings, in which:

FIG. 1 is a side elevational view, partly in section, of strip cleaningapparatus constructed in accordance with the invention;

FIG. 2 is a horizontal sectional view taken along the line 22 of FIG. 1and looking in the direction of the arrows, with parts broken away toshow the details of a preferred type of magnetostrictive transducer;

FIG. 3 is a vertical sectional view taken along the line 33 of FIG. 2and looking in the direction of the arrows;

FIG. 4 is a side elevational view, partly in section, of an alternativeembodiment of the invention; and

FIG. 5 is a side elevational view of still another embodiment of theinvention, with parts broken away for clarity.

3 DESCRIPTION OF A REPRESENTATIVE EMBODIMENT For convenience and toavoid redundancy, a repre-' sentative embodiment of the invention isdescribed herein with reference to the cleaning of motion picture film.It will be understood, however, that the invention is equally applicableto the cleaning of other perishable strip materials, such as magnetictapes, video tapes, and the like.

Referring first to FIG. 1, film cleaning apparatus constructed inaccordance with the invention includes a cleaning chamber of anyconvenient configuration, for example, square, rectangular or circular,as space considerations may require. A bath 12 of a solvent suitable forcleaning the film is provided within the chamber 10 in suflicientquantity to receive, and preferably submerse, an electromechanicaltransducer 14.

In accordance with an important feature of the invention, the transducer14 is generally cylindrical in form, having a hollow, axial bore 16extending therethrough which is open to the solvent bath at least at oneend. Any suitable electromechanical transducer may be used, includingthose of the magnetostrictive, electrostrictive and piezoelectric types.It need only be suificiently compatible with the solvent to be usedwithout an elaborate protective housing for the vibratory elements andhave a capacity sufficient to agitate vigorously the portion of thesolvent bath contained within the axial bore 16. To this end,appropriate electrical leads (not shown) are provided to connect thetransducer to a source of electrical power.

While cylindrical transducers are preferred, because of the savings inspace and the amount of solvent required flowing from thatconfiguration, other forms of hollow transducers can be used. It will beunderstood, therefore, that the transducer is described herein ascylindrical merely to indicate the preferred type of transducer.

In the embodiment of the invention depicted in FIGS. 1 to 3, the film 18to be cleaned passes from a feed reel (not shown) and over a guide roll20 to be guided downward toward the vertically oriented bore 16 of thetransducer 14. The film is received in its downward run 18a by a returnroll 22 which reverses the direction of movement of the film and directsit in an upwardly run 18b that, as shown, is generally parallel to thedownward run 18a. In the upward run 18b, the film is rinsed in aconventional manner by sprays of clean solvent issuing from a pair ofopposed spray heads 24 and is thereafter passed to a dryer (not shown)where solvent adhering to the film surfaces is removed. If desired, athird guide roll 26 may be provided to maintain the upward run 18b ofthe film in proper alignment with the spray heads 24 and the dryer.

The guide rolls 20 and 26 are mounted in a rotatable manner on shafts 28and 30, respectively, carried by a wall 10a of the cleaning chamber 10(see FIG. 3). Similarly, the transducer 14 is also supported, as by thebrackets 32, from the wall 10a, Other mounting arrangements for therolls and transducer may of course be used, the foregoing being merelyillustrative of one possible arrangement.

In contrast to the rolls 20 and 26 which are fixed, the return roll 22is intended to move vertically through the transducer bore 16 between anupper position, shown in the drawings in solid lines, and a lowerposition, shown in dashed lines. To this end, the roll 22 is slidablymounted on a guide track 34 which extends through the transducer boreand is rigidly attached at either end to the chamber wall 10a bybrackets 36.

Any suitable means may be used to secure the roll 22 to the guide track34, so long as sliding movement of the roll along the track isfacilitated and placement on or removal from the roll of the film is notimpeded. Advantageously, the track 34 is generally T-shaped in crosssection (see FIG. 2) and the roll 22 is rotatably carried at one endonly by a generally C-shaped slide 38 that fits in sliding relation overthe T-shaped track 34. A cable 40 connected at either end to the upperand lower ends, respectively, of the slide 38 forms with the slide acomplete loop that passes tautly over a driven pulley 42 at its upperend and an idler pulley 44 at its lower end.

The shaft 46 of a reversible electric motor 48 (see FIG. 3) drives thepulley 42, and through it the cable 40, either clockwise orcounterclockwise, as the case may be, to raise or lower, respectively,the return roll 22. The shaft 46, and a corresponding shaft 50 for theidler pulley 44, may be conveniently journaled in lugs 52 formed on thebrackets 36 supporting the guide track 34, while the electric motor 48preferably is mounted outside of the cleaning chamber wall 10a.

Appropriate electrical controls (not shown) are provided so that themotor 48 can be selectively energized to reciprocate the return roller22 between the upper and lower positions. If desired, microswitches (notshown) connected in the motor energization circuit may be locatedadjacent each end of the guide track 34 to be contacted by the slide 38.and hence deenergize the motor, when it reaches the proper endpositions. These positions, ideally, are axially outward of the ends ofthe transducer bore 16. So spaced from the bore, the roll 22 and itsassociated mounting structure are not directly exposed to the high levelultrasonic energy within the bore, and, perhaps more importantly, thefilm is subject to the cleaning action of the solvent over the fulllength of the transducer.

By the foregoing construction, significant advantages are realized bythe present invention over prior art film cleaning apparatus. Inparticular, it will be appreciated that by passing the film through thebore of the trandsucer in a double run higher film feed rates areobtainable without any sacrifice in the thoroughness with which the filmis cleaned. Consequently, the film can be cleaned in a correspondinlyshorter time, with the result that it is more quickly available forfurther use. Also, the cleaning apparatus is freed sooner for processingother film.

Another important feature of the invention is that the guide roll 20,return roll 22, and the guide roll 26, if used, are readily accessiblefor threading of the film over the rolls and, conversely, for removingthe film from the rolls at the end of a cleaning run or in the event acleaning run is interrupted. This results in part because the guiderolls 20 and 26 and the upper, or threading, position of the return roll22 are spaced outside of the adjacent end of the transducer bore 16, andpreferably are located above the level of the solvent bath 12 (see FIGS.1 to 3 and 5).

It will be appreciated, therefore, that the film may be quite easilythreaded over and removed from the rolls when the return roll 22 is inthe upper position.

It is significant also that the invention includes a very simple, yethighly reliable, provision for introducing the film into and forwithdrawing the film from the solvent bath 12. Thus. after the film hasbeen threaded over the guide roll 20 and return roll 22, the motor 48 isenergized to move the return roll from the threading position to thelower, or running, position where it remains throughout the cleaningrun. At the end of the cleaning run, or in the event of an interruptionin the run, the film may be withdrawn from the solvent bath simply byagain energizing the motor 48, this time in the reverse direction, toraise the return roll 22 to the threading position. The film istherefore at all times easily recoverable intact from the solvent bath,with virtually no risk that the soft film surfaces will be damaged orthat the film will be broken.

Economies of space and operation are also realized by the inventioninasmuch as both the size of the solvent chamber 10 and the quantity ofsolvent required for the bath 12 are minimized. As is more fullydescribed hereinafter, further economies of this nature can be obtainedby eliminating the separate cleaning chamber 10 and gtilizing thetransducer 114, in effect, as a cleaning cham- In any event, theinvention affords a compact, yet highly eflicient, cleaning unit that isadapted for use in a variety of applications. One such application, forwhich it is particularly suited, is in the film cleaning apparatus ofthe copending application Ser. No. 838,760, filed July 3, 1969 byMessrs. Arthur J. Miller, Raymond Perkms and Harold E. Sullivan. Thatapparatus incorporates solvent recovery and recycling systems whichcomplement, and hence enhance, the solvent saving characteristicsinhering to the present invention.

In applications where space limitations are of secondary importance, thetransducer 14 may be arranged honzontally within the cleaning chamber 10(see FIG. 4). With this arrangement, the guide roll 20' and the returnroll 22 when at the running position, that is, when at the right handend of the guide track 34 as viewed in FIG. 4, cooperate to pass thefilm 18 through the bore 16 1n two generally horizontal runs 180 and18d. On the return run 18d the film passes over a guide roller 54, whichmay be mounted on the bracket 36 for the guide track 34 or on a wall ofthe cleaning chamber 10, and is directed vertically out of the solventbath 12 toward the spray heads 24 and the dryer.

As indicated in FIG. 4, the guide rollers 20 and 54, the return roller22, and of course the guide track 34 and its associated cable 40 andpulleys 42 and 44 are all submerged in the solvent bath. Accordingly,when it is desired to thread the film 1 8 on or to remove it from therolls, the solvent bath preferably is drained otf to a level 56 somewhatbelow the position of the rolls. The reversible motor (not shown) usedto reciprocating the return roll 22 along the guide track 34 is,however, preferably mounted above the solvent bath. For this purpose, asecond pulley groove is provided on the pulley 42 to receive an endlesscable 58 leading from a drive pulley '60 on the motor shaft 46.

As previously mentioned, the size of the cleaning apparatus can bereduced still further by using the transducer itself as the cleaningchamber and eliminatiing the separate cleaning chamber 10. In theembodiment of the invention shown in FIG. 5, therefore, the verticallyextending bore 16 of the transducer 14 is capped at the lower end by anenclosure 62 has an axial length sufiicient to allow the runningposition of the return roll 22 to be spaced axially below the bottom endof the transducer bore 16 so as not to subject the roll 22, slide 38 andidler pulley 44 to the intense ultrasonic energy existing within thebore. This of course is merely the preferred arrangement, and, ifdesired, the running position of the return roll 22 may be locatedwithin the bore 16. In the latter instance, the bottom end of thetransducer 16 may simply be closed olf with a plate to confine thesolvent bath 12 within the bore.

Although the cap 62 is represented as being separate from thetransducer, it will be appreciated that it may be formed integrallytherewith. Also, even if separate, it need not be flanged as depicted inFIG. 5, but may take any suitable configuration as design considerationsmay require. Similarly, the guide track 34 may be attached to the cap 62in any suitable manner, for example, by screw fastners (not shown)received in the bottom or side wall of the cap.

Returning now to FIGS. 2 and 3, the structural details are shown of amagnetostrictive transducer that is especially suited for use with thepresent invention. Such a transducer is the subject of United StatesPat. No. 3,406,- issued 1 1968 to the Westinghouse Electric Corporation,Pittsburgh, Pa., and includes, in brief, a hollow cylinder 64 and one ormore arrays 66 of annular magnetostrictive elements 68 in vibratorycoupling at their inner peripheries to the outer circumferential wall ofthe cylinder 64. An energizing coil 70 is toroidally wound around thearrays 66, with the turns 72 of the coil 70 being received within axialslots 74 formed in the outer wall of the cylinder 64.

Upon energization of the coil 70, the arrays '66 of magnetostrictiveelements are caused to vibrate in a radial mode with respect to the axisof the cylinder 64, thereby imparting a corresponding radial vibrationto the cylinder member 64 and hence to the solvent bath 12 locatedwithin the bore of the cylinder. Because of the high sound intensitylevels generated within the bore 64 by this transducer construction, thesolvent bath is vigorously agitated throughout both the axial and radialextents of the bore. Both sides of the film are accordingly subjected toa very thorough cleaning action as the film travels through thetransducer bore.

It will be understood by those skilled in the art that theabove-described embodiments are intended to be merely exemplary, in thatthey are susceptible of modification and variation without departingfrom the spirit and scope of the invention as defined in the appendedclaims.

I claim;

1. Apparatus for ultrasonically cleaning strip material comprising:

a generally cylindrical electromechanical transducer having an axialbore open at at least one end, the transducer being adapted to directultrasonic vibrations radially into the bore,

means for providing a solvent bath within the bore to be agitated by theultrasonic vibrations, and

means for passing a strip of material axially through the bore in onedirection and for returning it axially through the bore in the oppositedirection to expose the strip to the ultrasonically agitated solventwithin the bore.

2. Apparatus according to claim 1 in which the means for passing thestrip through the bore includes:

a first roll positioned adjacent the one end of the transducer bore forguiding the strip into the bore in the one direction,

a second roll for receiving the strip moving in the one direction fromthe first roll and for guiding it in the return direction, and

means for reciprocating the second roll axially through the bore betweena threading position adjacent the one end of the bore and a runningposition adjacent the other end of the bore, the second roll when at therunning position adjacent the other end of the bore, the second rollwhen at the running position cooperating with the first roll to pass thestrip axially through the bore in the one direction and to return itaxially through the bore in the opposite direction and when at thethreading position to facilitate threading of the strip on and removalof the strip from the rolls.

3. Apparatus according .to claim 2 in which the means for reciprocatingthe second roll includes:

a iuide track extending axially through the transducer ore,

means for mounting the second roll on the guide track for slidingmovement therealong, and

drive means forvselectively sliding the second roll along the trackbetween the threading position and the running position.

4. Apparatus according to claim 3 in which the position of the firstroll and the threading position of the second roll are spaced axiallyoutward of the one end of the transducer bore.

5. Apparatus according to claim 4 in which:

the longitudinal axis of the transducer bore is located in (a; generallyvertical plane with one end uppermost, an

the position of the first roll and the threading position of the secondroll are above the level of the solvent bath, thereby to withdraw thestrip from the solvent bath when the second roll is at the threadingposition.

6. Apparatus according to claim 4 in which:

the transducer bore is open at both ends,

the runing position of the second roll is spaced axially outward of theother end of the bore, and

the means for providing a solvent bath within the bore includes meansenclosing in fluid tight relation the other end of the bore and therunning position of the second roll.

7. Apparatus according to claim 4 in which the means for providing asolvent bath within the transducer bore include:

a chamber containing a solvent bath, and

means for mounting the transducer within the chamber with the one end incommunication with the solvent bath.

8. Apparatus according to claim 7 in which:

the transducer bore is open at both ends, at least one of which is influid communication with the solvent bath in the chamber, and

the runing position of the second roll is spaced axially outward of theother end of the bore.

9: Apparatus according to claim 8 in which:

the longitudinal axis of the transducer bore is located in a generallyvertical plane, and

the first roll and the threading position of the second roll are abovethe level of the solvent bath within the chamber, thereby to withdrawthe strip from the solvent bath when the second roll is at the threadingposition.

10. Apparatus according to claim 8 in which:

the longitudinal axis of the transducer bore is located in a generallyhorizontal plane, and

the means for passing the strip through the bore further includes athird roll for receiving the strip moving in the return direction andfor guiding it vertically out of the solvent bath.

11. Apparatus according to claim 1 in which the transducer comprises amagnetostrictive transducer having a hollow cylinder member and an arrayof annular magnetostrictive elements in vibratory coupling at its innerperiphery to the outer circumferential wall of the hollow cylindermember, whereby the solvent located within the transducer lbore isvigorously agitated by high intensity sound energy.

12. A method for ultrasonically cleaning strip materials comprising:

providing a solvent bath within the bore of a generally cylindricaltransducer having an axial 'bore therethrough,

energizing the transducer to agitate ultrasonically the solvent withinthe transducer bore,

passing a strip of material to be cleaned axially through the transducerbore in one direction and returning the strip of material axiallythrough the transducer bore in the opposite direction, thereby tosubject the strip material to the cleaning action of the ultrasonicallyagitated solvent within the bore.

13. A method according to claim 12 in which the strip material is passedthrough the transducer bore by:

threading the strip material over first and second rolls positionedaxially outward of one end of the bore, and

moving the second roll with the strip material thereon axially throughthe bore to a position axially outward of the other end of the bore.

14. A method according to claim 13 further comprising withdrawing thestrip material intact from the solvent bath after cleaning.

15. A method according to claim 14 in which the strip material iswithdrawn from the solvent bath by returning the second roll axiallythrough the transducer ibore to a position axially outward of the oneend of the bore.

16. A method according to claim 15 in which the strip material is easilydamaged, fragile material.

17. Apparatus according to claim 1 in which the strip material is easilydamaged, fragile material.

References Cited UNITED STATES PATENTS 2,967,119 1/1961 Gutterman 13413,052,244 9/1962 Gley 1341X 3,099,584 7/1963 Walsh 1341 3,240,963 3/1966Sasaki 134-1X MORRIS O. WOLK, Primary Examiner J. T. ZATARGA, AssistantExaminer US. Cl. X.R. l34'-15,l22,184

2 3 UNETEE STATES ewes? ossies CETIFICATFE Ci CCRRECWCN Patent No.3,582,400 Dated June 1, 1971 Inventofl Arthur J. Miller It is certifiedthat error zap-geese in the above-identified patent and that saidLetters Patent are hereby corrected as shown below:

Column Column Column Column line 57, comma should be period line 21,period should be comma line 32,,"tradedsneer should be --trensduoer--;

line 36, "correspondinly" should be --oor'i"espondingly--,'

line &0, after "62" insert --whioh is bolted,

welded or otherwise sealingly connected to the lowerend of thetransducer. Preferably the enclosure 62--;

Column 6, line 40, omit "adjacent the other end of the bore, the secondroll when at the running position";

Column 6, line 63, insert after "with" --the-;

Column 7, line 1 "Tuning" should be running--.

were bub Column Signed and sealed this 25th day oi A il 1972.

(SEAL) Attest:

EDWARD PhFLETCl-"ERJR. ROBERT G-CTTSCHALK Attesting Officer Commissionerof Patents

